toxin

toxin

[tok´sin]

a poison, especially a protein or conjugated protein produced by certain animals, higher plants, and pathogenic bacteria. Bacterial toxins characteristically do not cause symptoms until after a period of incubation while the microbes multiply, or (as happens with botulism) the preformed toxin reaches and affects the tissue. Usually only a few toxin-producing agents are introduced into the body, and it is not until there are enough of them to overwhelm the leukocytes and other types of antibodies that symptoms occur. In some cases of food poisoning, symptoms are almost immediate because the toxin is taken directly with the food. Toxins can cause antitoxins to form in the body, thus providing a means for establishing immunity to certain diseases.

botulinal toxin (botulinum toxin) (botulinus toxin) one of seven type-specific, immunologically differentiable exotoxins (types A to G) produced by Clostridium botulinum,neurotoxins usually found in imperfectly canned or preserved foods. They cause botulism by preventing release of acetylcholine by the cholinergic fibers. Type A is one of the most powerful poisons known; it is also used therapeutically by injection to inhibit muscular spasm in the treatment of dystonic disorders such as blepharospasm and strabismus, to treat wrinkles of the upper face, and to reduce anal sphincter pressure to promote healing of chronic anal fissure. Type B is injected in treatment of cervical dystonia. Called also botulin.

cholera toxin an exotoxin produced by Vibrio cholerae; a protein enterotoxin that binds to the membrane of enteric cells and stimulates the adenylate cyclase system, causing the hypersecretion of chloride and bicarbonate ions, resulting in increased fluid secretion and the severe diarrhea characteristic of cholera.

diphtheria toxin a protein exotoxin produced by Corynebacterium diphtheriae that is primarily responsible for the pathogenesis of diphtheria and related infections; it is an enzyme that activates transferase II of the mammalian protein synthesizing system.

diphtheria toxin for Schick test a sterile solution of the diluted, standardized toxic products of Corynebacterium diphtheriae; used as a dermal reactivity indicator in the schick test of immunity to diphtheria.

dysentery toxin any of various exotoxins produced by species of Shigella; the one formed by S. dysenteriae serotype 1 is a potent neurotoxin with hemorrhagic and paralytic properties.

erythrogenic toxin a bacterial toxin from certain strains of Streptococcus pyogenes that produces an erythematous reaction when injected intradermally and is responsible for the rash in scarlet fever.

tetanus toxin the potent exotoxin produced by Clostridium tetani, consisting of two components, one a neurotoxin (tetanospasmin) and the other a hemolysin (tetanolysin).

tox·in

(tok'sin),

A noxious or poisonous substance that is formed or elaborated either as an integral part of the cell or tissue (endotoxin), as an extracellular product (exotoxin), or as a combination of the two, during the metabolism and growth of certain microorganisms and some higher plant and animal species.

[G. toxikon, poison]

toxin

/tox·in/ (tok´sin) a poison, especially a protein or conjugated protein produced by some higher plants, certain animals, and pathogenic bacteria, that is highly poisonous for other living organisms.

bacterial toxins toxins produced by bacteria, including exotoxins, endotoxins, and toxic enzymes.

botulinal toxin , botulinum toxin, botulinus toxin an exotoxin produced by Clostridium botulinum that produces paralysis by blocking the release of acetylcholine in the central nervous system; there are seven immunologically distinct types (A–G). Type A is used therapeutically to inhibit muscular spasm in the treatment of dystonic disorders such as blepharospasm and strabismus, as well as to treat wrinkles of the upper face; type B is used to treat cervical dystonia.

clostridial toxin one produced by species of Clostridium, including those causing botulinus, gas gangrene, and tetanus.

diphtheria toxin a protein exotoxin produced by Corynebacterium diphtheriae that is primarily responsible for the pathogenesis of diphtheritic infection; it is an enzyme that inhibits protein synthesis.

toxin

(tŏk′sĭn)

n.

1. A poisonous substance, especially a protein, that is produced by living cells or organisms and is capable of causing disease when introduced into the body tissues but is often also capable of inducing neutralizing antibodies or antitoxins.

2. A poisonous or harmful nonbiological substance, such as a pollutant.

toxin

[tok′sin]

a poison, usually one produced by or occurring in a plant or microorganism. See also endotoxin, exotoxin.

tox·in

(tok'sin)

1. A noxious or poisonous substance that is formed or elaborated as an integral part of the cell or tissue, as an extracellular product (exotoxin), or as a combination of the two during the metabolism and growth of certain microorganisms and some higher plant and animal species.

2. A common misnomer for poison.

[G. toxikon, poison]

toxin

Any substance produced by a living organism that is poisonous to other organisms. Bacterial disease is largely the result of poisoning by the toxins they produce. Some bacteria release soluble exotoxins that act remotely. Others produce only endotoxins which operate only locally. Some bacterial toxins are among the most poisonous substances known.

toxin

a nonenzymic metabolite of one organism which is injurious to another organism. see TETANUS, BOTULISM.

Toxin

A poison. In the case of scarlet fever, the toxin is secreted as a byproduct of the growth of the streptococcus bacteria and causes a rash.

toxin,

n poisonous material that is synthesized or derived from an animal, mineral, or plant.

tox·in

(tok'sin)

Noxious or poisonous substance formed or elaborated either as an integral part of the cell or tissue (endotoxin), as an extracellular product (exotoxin), or as a combination, during metabolism and growth of some microorganisms and some higher plant and animal species.

[G. toxikon, poison]

toxin (tok´sin),

n a poisonous protein made by specific animals, higher levels of plants, and disease-causing bacteria.

toxin

a poison, especially a protein or conjugated protein produced by certain animals, some higher plants, and pathogenic bacteria. Antigenic toxins, produced by bacteria or helminths, stimulate production of antitoxins. Exotoxins are produced by bacteria and diffuse into surroundings, e.g. tetanus toxin, or can be ingested preformed, e.g. botulinum toxin. Endotoxins are released into the surrounding tissue only when the bacteria break down. They are lipopolysaccharides and form part of the cell wall, e.g. coliform endotoxins. Metabolic toxins, e.g. toxic amines absorbed from damaged intestine, ketones, lactic acid from carbohydrate engorgement, ammonia in liver damage, creatinine in renal dysfunction. See also metabolic toxins.

dermonecrotic toxin

an exotoxin produced by certain bacteria that causes extensive local necrosis on intradermal inoculation.

extracellular toxin

exotoxin.

intracellular toxin

endotoxin.

tetanus toxin

the potent neurotoxic exotoxin produced by Clostridium tetani. Called also tetanospasmin.

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